ylluminarious has been developing a library called opal-phaser since late 2014: "Essentially, it lets you write Phaser code with Ruby. It does this by using the Opal source-to-source compiler and, of course, by using Phaser. I created this project because I really like Phaser and I prefer the expressiveness and readability of the Ruby language.
You might be wondering if this is a toy project, but it’s not. I have already created multiple games with opal-phaser and reworked a decent amount of the example suite from the official Phaser Examples. I also created the site for opal-phaser with opal-phaser and the Volt web framework (another very interesting and useful project that uses Opal to great advantage)."
You can discuss opal-phaser further in this forum thread, or check out the official site.